1. Field of the invention
The present invention relates to a semiconductor device, and more particularly, to the improvement of an input circuit thereof.
2. Description of the Related Art
In a semiconductor device, an input circuit is provided for inputting an input signal of a TTL level and converting it into a signal of a MOS level.
A first prior art input circuit receives a ground voltage from a ground pad which is individually provided from ground pads for functional circuits such as address decoders, sense amplifiers, and data output buffers (See: JP-A-HEI3-183159). This will be explained later in detail.
In the first prior art input circuit, however, since the number of pads is increased, the integration of the device is reduced.
In order to enhance the integration of the device, a ground pad is provided commonly for the input circuit and a functional circuit, to reduce the number of pads. This will be explained later in detail.
In the second prior input circuit, however, since noise due to the operation of the functional circuit is applied via the ground pad to the input circuit, the access speed of the input circuit is decreased, and accordingly, the access speed of the device is decreased.